


Immunization

by CharmsDealer



Category: Life with Derek
Genre: F/M, Season 1, Situational Humiliation, Step-Sibling Incest, aggressive milk warfare, apparently I have a thing for Derek being kind of gross and not very nice, descriptive milk drinking, gross!kink, non consensual licking, spit, very mild though
Language: English
Status: Completed
Published: 2015-06-30
Updated: 2015-06-30
Packaged: 2018-04-07 00:23:28
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 747
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4242399
Author URL: https://archiveofourown.org/users/CharmsDealer/pseuds/CharmsDealer
Summary: <blockquote class="userstuff">
              <p>Casey is growing tired of Derek's gross habit of drinking milk straight out of the carton. When she takes it up with him, he responds in a mature, understanding way...By slobbering all over her neck.</p>
            </blockquote>





	Immunization

Derek drinks milk straight from the carton. He puts his whole mouth over the opening. He takes greedy, noisy gulps and makes low, deeply contented moaning noises whenever he has an audience (Casey). Sometimes his mouth comes un-stuck and he slurps at the lip until he’s latched back on, but not before some milk has dribbled down his chin, down his collar and under his shirt.

They go through so. Much. Milk.

But that’s beside the point. It’s unhygienic and totally inconsiderate and it drives Casey _insane_.

When Casey unsuspectingly walks in on Derek with his tongue down the milk carton that morning, she strongly resists the urge to throw up.

Derek stares at her brazenly. He takes a long pull of milk and she watches, with sick fascination, the way his throat moves as he swallows. The corner of his mouth kicks up smugly when she wrinkles her nose and flicks her eyes away. He’s utterly shameless.

Derek’s mouth separates from the milk with a loud, sucking pop and he makes a big show of smacking his lips, “Saved some for ya.”

“Ew,” Casey says, mourning her life. Mourning her future.

Derek snickers and puts the milk back in the fridge. He looks Casey up and down in one long sweep and she makes a face at him. Yes, she is still in her pyjamas. No, she isn’t at the top of her game this morning. She woke up feeling oddly groggy and isn’t really up to today’s breakfast argument.

Derek, unfortunately, can smell weakness.

“You know there’s a way for you to do that without being totally gross,” Casey says primly.

Derek raises an eyebrow. “And that’s supposed to interest me?”

A muscle jumps in Casey’s jaw. “Look, I’m just saying that if you don’t want to go to the trouble of getting a glass out you could at least try not to slobber all over everything. You can just pour it into your mouth like _this,_ see?” She pushes past him and opens the fridge. She spots a carton of apple juice that’s unopened and therefore safe.

She unscrews the cap and lifts the carton above her open mouth.

Derek, because he’s Derek, watches her with his arms folded, pretending to go along with her demonstration until the last possible second. Just as the juice is starting to fall he reaches out and knocks the carton with the heel of his palm. Juice goes everywhere.

Casey shrieks in surprise, dropping the carton on the floor. It bounces once and proceeds to bleed out, forgotten, as she launches herself at Derek.

Derek holds her away with one arm and laughs at her as she thrashes and tries to get at his stupid smug face.

“You really should have seen that one coming, Case...”

“You’re VILE! You’re poisoning everyone with your disgusting saliva! You’re so gross and I hate you!”

Derek’s eyes narrow at her before his face suddenly splits into a grin. “Poison you say? Well, I suppose I’ll just have to make you immune.”

Suddenly, Derek is pulling her closer and bending his head low.

Casey squirms to get away but can only let out a strangled gasp, shocked beyond belief when she feels Derek’s tongue against her throat, chasing the sticky trails of drying juice. He lays a broad stripe from her collar bone to just under her chin and continues to drag his tongue up and down and across her skin. It’s warm and wet and squiggly and utterly revolting.

He drools on her skin with sloppy wet licks that make her shudder. Spit starts to cool in patches and some of it dribbles under her top’s spaghetti straps and oozes lower... It stinks like his mouth and milk and- “Get off get off get OFF!” Casey chant-squeals in horror as Derek liberally coats her in a thick layer of boy-slime.

“There. Vaccinated,” Derek pulls back. A string of saliva clings to his lip where it’s connected to her collar. His lips are shiny and wet and twisted at her in a sloppy sneer. “Do you have any other concerns you wish to air at this time?”

Casey’s mouth opens and closes. She might be broken. “You just...With your _mouth_ ,” she says reproachfully.

Derek lets go of her arms and steps away with a weird stiffness. “Then, in that case, I’m going to get dressed.”

Casey stars after Derek with a mixture of outrage and embarrassment. She needs like... ten showers.  _  
_

**Author's Note:**

> Just started Life with Derek, immediately slapped with the UST/BST and now, for some reason...
> 
> THIS? I don't know what this is really, I just wanted to write SOMETHING and I have at least four crack-tastic scenarios lined up in my brain. Sometimes things are better in my brain than on 'paper'. This was kind of frustrating to write but I hope it finds people somewhere.


End file.
